Jose Mourinho, who is also pursuing a deal for Shakhtar Donetsk and Brazil midfielder Fred, wants to sign a centre-half this summer as the United manager bids to strengthen his defence and believes Alderweireld would be a good fit.

But Pochettino has made it clear to Levy, both publicly and in talks with the Spurs chairman, that he wants the club to conduct their business earlier than in previous summers, both in terms of ins and outs, and United hope that stance could assist any approach for Alderweireld.

Spurs have traditionally left business late but, with a shortened transfer window compounded by the World Cup finals, which will further limit time to do deals, Pochettino hopes the club do not drag their heels and wants the go-ahead to sell anybody he believes he can replace. Levy is eager for Pochettino to sign a new contract and knows he may have to bow to some of the manager’s wishes.

Pochettino wants Spurs to wrap up their transfer business early on this summerCredit: Getty Images

It would still take a huge offer to persuade Levy to sell Alderweireld to a direct English rival for the Champions League places. Alderweireld would be available for £25m next summer [2019] under the terms of his contract, which has two years to run, but Spurs want more than double that this summer. There have even been reports that Levy could hold out for a fee closer to the £75m Liverpool paid Southampton for Virgil van Dijk in January, although such a price seems excessive given Alderweireld’s age and contractual situation.

Still, it remains to be seen if Ed Woodward, the United executive vice-chairman, is prepared to go the extra yard to secure the services of Alderweireld, who, at 29, would have little resale value and likely be bought with immediate success in mind.

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Woodward was unwilling to meet Inter Milan’s £49m asking price for Croatia winger Ivan Perisic last summer, much to Mourinho’s frustration, because it was considered an excessive sum for a player who was 28 at the time. Woodward was also conscious that United – who have also been linked with Spurs left back Danny Rose - paid Chelsea a projected £40m fee for the 29-year-old Serbia midfielder, Nemanja Matic, that summer.

Pochettino is a keen admirer of Anthony Martial but United are opposed to selling the France forward, who has also attracted interest from Chelsea, to an English club. If Tottenham insisted on taking Martial as part of any negotiations over Alderweireld, a deal for the defender could easily break down and force United to pursue other central defensive targets.

The sale of Martial to any club, let alone an English rival, would be dimly received by United supporters, though.

He has endured an up and down season in which he has struggled to hold down a regular starting place, failing to make France’s World Cup squad in the process, and he is one of several players who has a difficult relationship with Mourinho. But his talent is considerable and there are plenty of people within Old Trafford who feel the club would be making a huge mistake that could come back to haunt them if Martial was sold.

With Michael Carrick retiring, a midfielder remains Mourinho's first priority and the Portuguese is hoping to land Fred, whom Manchester City have also pursued previously, before the start of the World Cup finals next month.